The primary objective is to elucidate the interaction between environmental events (particularly social) and circulating levels of gonadal hormones. We are attempting to identify the stimulus properties which elicit or inhibit aggressive and sexual responses and to determine the interactive effects of seasonal diurnal and phyletic variables. Differential social experiences within a group will be correlated to changing social behavior and gonadal activities in an ontogenetic study of these interactions. Male-female comparisons include a search for a model of the female hormonal system comparable to the feedback loop model of testosterone and behavior in the male. We will make selective use of gonadotrophin administrations to ascertain the relative influence of hormonal parameters on the behavior of animals living in groups. Hormonal measures are made systematically via radioimmunoassay techniques. Behavioral measures are obtained both from intact groups and from individuals and groups scored during systematic manipulations of group compositions. Selected activities are quantitatively measured using frequency and duration measures as appropriate. Focal animal time sampling tchniques as well as continuous protocols are used in measuring various aspects of behavior.